From 4588b025c88f5eeb3b22a9d333db28e7dc1e033f Mon Sep 17 00:00:00 2001
From: Caio Oliveira <caio.oliveira@intel.com>
Date: Sat, 28 Feb 2026 11:56:05 -0800
Subject: [PATCH] spirv: Pull constant source fixup to the existing loop

Backport-to: 26.0
Reviewed-by: Georg Lehmann <dadschoorse@gmail.com>
(cherry picked from commit b0c3b20bff4e6593f73fa554040fc6e6ede62e29)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40359>
---
 .pick_status.json                 |  2 +-
 src/compiler/spirv/spirv_to_nir.c | 36 ++++++++++++++++---------------
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index 3465c28c68f..fb69677b91d 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -3024,7 +3024,7 @@
         "description": "spirv: Pull constant source fixup to the existing loop",
         "nominated": true,
         "nomination_type": 4,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null,
         "notes": null
diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c
index deacf97f7ec..1b863640fea 100644
--- a/src/compiler/spirv/spirv_to_nir.c
+++ b/src/compiler/spirv/spirv_to_nir.c
@@ -2936,26 +2936,28 @@ vtn_handle_constant(struct vtn_builder *b, SpvOp opcode,
                else if (glsl_type_is_e5m2(org_src_type))
                   src[j][c].f32 = _mesa_e5m2_to_float(src[j][c].u8);
             }
-         }
 
-         /* fix up fixed size sources */
-         switch (op) {
-         case nir_op_ishl:
-         case nir_op_ishr:
-         case nir_op_ushr: {
-            if (bit_size == 32)
-               break;
-            for (unsigned i = 0; i < num_components; ++i) {
-               switch (bit_size) {
-               case 64: src[1][i].u32 = src[1][i].u64; break;
-               case 16: src[1][i].u32 = src[1][i].u16; break;
-               case  8: src[1][i].u32 = src[1][i].u8;  break;
+            /* Fix up source to respect NIR expected sizes. */
+            switch (op) {
+            case nir_op_ishl:
+            case nir_op_ishr:
+            case nir_op_ushr: {
+               /* Shift amount in NIR ops must be 32-bit. */
+               vtn_assert(!swap);
+               const unsigned shift_idx = 1;
+               const unsigned shift_bit_size = glsl_get_bit_size(src_val->type->type);
+               if (i != shift_idx || shift_bit_size == 32)
+                  break;
+               for (unsigned c = 0; c < src_comps; c++) {
+                  nir_const_value *shift = &src[shift_idx][c];
+                  *shift = nir_const_value_for_uint(
+                        nir_const_value_as_uint(*shift, shift_bit_size), 32);
                }
+               break;
+            }
+            default:
+               break;
             }
-            break;
-         }
-         default:
-            break;
          }
 
          nir_const_value *srcs[3] = {